JP5227077B2 - 3-phase rotating electric machine - Google Patents

Description

  The present invention relates to a three-phase rotating electric machine, and more particularly, to a three-phase rotating electric machine in which coils wound around teeth are arranged close to each other.

  Inverter power supplies are widely used for driving three-phase rotating electrical machines. However, when a three-phase rotating electrical machine is driven by an inverter power supply, a high voltage may be generated in the three-phase rotating electrical machine due to a steep surge voltage generated when the inverter circuit is switched. Specifically, a plurality of teeth portions, a slot portion formed between adjacent teeth portions, and a three-phase coil wound around the teeth portions, wherein the in-phase coils are provided side by side in the circumferential direction. In a three-phase rotating electric machine including three-phase coils provided side by side in the radial direction, an electrostatic capacity is formed between a slot inner portion located in the slot portion and a tooth portion (ground) of each coil. When a steep surge voltage generated by switching of the inverter circuit is applied to the three-phase rotating electric machine, the current at the moment of rising at the time of applying the voltage is bypassed to the other-phase coil via the above-described capacitance. The above-mentioned current concentrates on the first coil which is a coil directly connected to each input terminal of the three-phase rotating electrical machine, so that the shared voltage of the first coil increases. When the potential difference between both ends of the first coil is large, if this potential difference exceeds the partial discharge start voltage, the insulation life of the coil may be shortened due to the occurrence of partial discharge.

  In Patent Document 1, a conductor of 2n (n is an integer) is wound by half the number of windings of the motor winding, and then the winding start and end conductors are divided into two, and the winding start n pieces and winding A low-voltage motor in which n conductors at the end are connected externally, including a connection portion at the start and end of winding of the winding of the low-voltage motor, a winding start portion of the winding, an inter-pole crossover wire, and a winding end portion The thing which connects a capacitor | condenser between is disclosed.

JP 2005-65363 A

  By using the configuration of Patent Document 1, it is possible to relax the voltage sharing between the coils with respect to the steep surge voltage, and to prevent the insulation deterioration in the coils from occurring. However, the configuration of Patent Document 1 requires a process of taking out and welding the wire at the start and end of winding of the motor winding, and it is necessary to install capacitors on all the windings wound in parallel. This may increase costs.

  An object of the present invention is to provide a three-phase rotary electric machine that relaxes the voltage sharing between coils when a steep surge voltage is input to the three-phase rotary electric machine with a simpler configuration and ensures insulation performance. .

The three-phase rotating electrical machine according to the present invention is a three-phase coil wound around a plurality of teeth portions, a slot portion formed between adjacent teeth portions, and the in-phase coils arranged in the circumferential direction. And a three-phase rotating electric machine including a three-phase coil in which different-phase coils are arranged side by side in the radial direction, and between the in-phase coils and between the different-phase coils in the coil end portion located outside the slot portion of each coil The relative dielectric constant of ε ₁ is ε ₁ , the relative dielectric constant between the inner portion of the slot located inside the slot portion of each coil and the tooth portion is ε ₂ , and ε ₁ is larger than ε ₂ And

In the three-phase rotating electrical machine according to the present invention, ε ₁ is preferably larger than 1.

In the three-phase rotating electrical machine according to the present invention, each coil is impregnated with a varnish having a relative dielectric constant of ε ₁ between the coil end portions, and in each coil, there is a gap between the slot inner portion and the tooth portion. the varnish relative permittivity of epsilon ₂ is impregnated is preferred.

Further, in the three-phase rotating electrical machine according to the present invention, the ratio between only the coil end portions from the first coil end portion to the third coil end portion on each input terminal side of the three-phase rotating electrical machine The dielectric constant is preferably ε ₁ .

In the three-phase rotating electrical machine according to the present invention, it is preferable that ε ₁ is larger than 5 and ε ₂ is smaller than 5.

In the three-phase rotating electrical machine according to the present invention, it is preferable that the coil end portions of each coil are insulated by insulating paper having a relative dielectric constant of ε ₁ .

According to the above configuration, since ε ₁ is higher than ε _{2, the} capacitance value formed between the coil end portions is formed between the slot inner portion and the tooth portion forming the slot portion. Larger than the capacitance value. Therefore, even if a steep surge voltage generated by switching of the inverter circuit is applied to the rotating electrical machine, the neutral point side opposite to the input terminal via the capacitance formed between the coil end portions A surge current flows into the coil arranged in the circuit. And since a high frequency current disperse | distributes to each coil, the concentration of the surge voltage to the 1st coil which is the 1st coil directly connected with an input terminal can be suppressed. Thereby, the insulation performance of a coil is securable.

  Embodiments according to the present invention will be described below in detail with reference to the accompanying drawings. Further, in this description, specific shapes, materials, numerical values, directions, and the like are examples for facilitating understanding of the present invention, and can be appropriately changed according to the use, purpose, specification, and the like.

  FIG. 1 is a top view of a three-phase rotating electrical machine 10 that is the first embodiment of the present invention. In FIG. 1, each phase coil is illustrated in a simplified manner for easy understanding of the coil winding state. The three-phase rotating electrical machine 10 includes a stator 8 that is a stator, a three-phase coil that is wound around the stator 8, and a rotor that is a rotor (not shown). The three-phase coil includes a U-phase coil 32, a V-phase coil 34, and a W-phase coil 36, and the U-phase coil 32, V-phase coil 34, and W-phase coil 36 are arranged in this order from the outer peripheral side of the stator 8. Be placed. Further, a U-phase input terminal 12, a V-phase input terminal 14, and a W-phase input terminal 16 are provided as input terminals for receiving an output from an inverter circuit (not shown). Here, the first coil directly connected to the U-phase input terminal 12, the V-phase input terminal 14, and the W-phase input terminal 16 is replaced with the first U-phase coil 321, the first V-phase coil 341, and the first W-phase, respectively. A coil 361 is defined. Further, a neutral point 13 is provided as a connection point between the U-phase coil 32, the V-phase coil 34 and the W-phase coil 36.

  The stator 8 includes a 48-pole tooth 22 around which a three-phase coil is wound, a slot 24 formed between the teeth 22, and a stator yoke 18. The stator yoke 18 has a donut shape that forms the outer shape of the stator 8. The teeth 22 have a substantially quadrangular frustum shape in which the thickness is tapered from the stator yoke 18 toward the inner diameter side of the stator 8. The U-phase coil 32, the V-phase coil 34, and the W-phase coil 36 are wound around the teeth 22 by being inserted into the slots 24 so as to straddle the five adjacent teeth 22.

  FIG. 2 is a cross-sectional view taken along the line AA in FIG. A U-phase coil 32 is inserted into the slot 24 and the teeth 22 are wound around the cross section along the line AA. At this time, the V-phase coil 34 and the W-phase coil 36 are extended without being inserted into the slot 24 here.

  The U-phase coil 32 includes a U-phase coil end portion 322 and a U-phase slot inner portion 324. The U-phase coil end portion 322 projects from the inside of the slot 24 in the U-phase coil 32 along the end face of the tooth 22, straddles the adjacent five teeth 22, and enters the inside of the slot 24 ahead of the slot 24. It is a part arranged outside. The U-phase slot inner portion 324 is a portion disposed inside the slot 24 so as to wind the tooth 22 along the side wall 221 of the tooth 22 forming the slot 24 in the U-phase coil 32. Similar to U-phase coil 32, V-phase coil 34 includes a V-phase coil end portion 342 and a V-phase slot portion (not shown), and W-phase coil 36 has a W-phase coil end. A portion 362 and a W-phase slot portion (not shown) are included.

Further, gaps 70 (see FIG. 1) between all the coil end portions of the same phase formed in the U phase coil end portion 322, the V phase coil end portion 342, and the W phase coil end portion 362, respectively, and all the coil ends of different phases. A varnish having a relative dielectric constant ε ₁ (for example, ε ₁ = 20) is impregnated so as to fill the gap 80 between the parts, and then heated and cured to form an object 51 that fills the gaps 70 and 80. Further, a varnish having a relative dielectric constant ε ₂ (eg, ε ₂ = 3) is impregnated so as to fill a gap 90 between each U-phase slot inner portion 324 and the corresponding side wall 221 of each tooth 22, and then heated. An object 52 that fills the gap 90 is formed by curing. Similarly, a varnish having a relative dielectric constant ε ₂ (eg, ε ₂ = 3) is filled so as to fill a gap 90 between each V-phase slot inner portion and each W-phase slot inner portion and the corresponding side wall 221 of each tooth 22. To form an object 52 that fills the gap 90. Here, the relative dielectric constant ε ₁ is set to a value larger than 1, which is the dielectric constant of air, more preferably larger than 5. The relative dielectric constant ε ₂ is preferably set to a value smaller than 5.

Capacitance 46 (relative permittivity ε ₁ ) is formed between each U-phase coil end portion 322 and each adjacent V-phase coil end portion 342 having a different phase, as shown in FIG. Thus, the electrostatic capacitance 42 (relative dielectric constant ε ₁ ) is formed between the U-phase coil end portions 322 that are provided adjacent to each other and have the same phase. Furthermore, a capacitance 44 (relative permittivity ε ₂ ) is formed between each U-phase slot inner portion 324 and the side wall 221 (ground) of the tooth 22. In the V-phase coil 34 and the W-phase coil 36, capacitances 42, 44, and 46 are similarly formed.

  Next, the operation of the three-phase rotating electrical machine 10 having the above configuration will be described with reference to FIGS. FIG. 3 is a circuit diagram showing the three-phase rotating electrical machine 10 in element units. When the three-phase rotating electrical machine 10 is driven by an inverter circuit, a surge voltage with a sharp rise and a high peak voltage is generated between the phases at the moment of switching of the inverter circuit. Applied to the input terminal. For example, when this surge voltage is applied to the U-phase input terminal 12, another V adjacent to the first U-phase coil 321, which is the first coil from the U-phase input terminal 12 side, via the capacitance 44. A path through which a current flows from the phase input terminal 14 side to the first V-phase coil 341 that is the first coil and the first W-phase coil 361 that is the first coil from the W-phase input terminal 16 side, and a first U-phase coil 321 The second U-phase coil 323 that is the second coil from the adjacent U-phase input terminal 12 side and the second coil from the V-phase input terminal 14 side through the capacitance 42 and the capacitance 46 that are in contact with each other. There is a path through which current flows into second V-phase coil 343.

Here, since the relative dielectric constant ε ₁ > the relative dielectric constant ε ₂ , the values of the capacitance 42 and the capacitance 46 are larger than the value of the capacitance 44. Therefore, the surge current flowing in the three-phase rotating electrical machine 10 by applying the surge voltage flows into the second U-phase coil 323 through the electrostatic capacitance 42 and into the second V-phase coil 343 through the electrostatic capacitance 46. Further, since the capacitance values of the capacitance 42, the capacitance 44, and the capacitance 46 in contact with the second U-phase coil 323 are as described above, the third coil from the U-phase input terminal 12 side is used. A surge current flows from the third U-phase coil 325 and the V-phase input terminal 14 side to the third V-phase coil 345 that is the third coil, and further to the neutral point 13 side.

  Similarly, when a surge voltage is applied to the V-phase input terminal 14 or the W-phase input terminal 16, it is directed to the coil on the neutral point 13 side via the capacitances 42 and 46 without passing through the capacitance 44. Surge current flows in. Thus, since the surge current flows toward the coil on the neutral point 13 side, the high-frequency current to each coil is dispersed, so that the surge voltage is concentrated on the first V-phase coil 341 and the first W-phase coil 361. Can be suppressed. Thereby, the insulation performance of the U-phase coil 32, the V-phase coil 34, and the W-phase coil 36 can be ensured.

In the above description, the gaps 70 and 80 between all the in-phase and out-of-phase coil end portions formed in the U-phase coil end portion 322, the V-phase coil end portion 342, and the W-phase coil end portion 362, respectively (FIG. 1, FIG. 2), the varnish having a relative dielectric constant ε ₁ is impregnated. However, as described above, not all coil end portions from each input terminal to the neutral point 13, for example, the first U-phase coil 321, the first V-phase coil 341, and the first W-phase coil 361 of the three-phase rotating electrical machine 10. Varnish having a relative dielectric constant ε ₁ so as to fill gaps 70 and 80 between the coil end portions from the coil end portions to the coil end portions of the third U-phase coil 325, the third V-phase coil 345, and the third W-phase coil 365. It is good also as what is impregnated.

  Next, a three-phase rotating electrical machine 11 that is a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a top view of the three-phase rotating electrical machine 11 according to the second embodiment of the present invention. 5 is a cross-sectional view taken along line AA in FIG. Here, since the three-phase rotating electrical machine 11 has substantially the same configuration as that of the three-phase rotating electrical machine 10 of the first embodiment, the same constituent elements are denoted by the same reference numerals and redundant descriptions are incorporated by reference. Omitted, a different configuration and its operation will be described. Since the three-phase rotating electrical machine 11 is different only in the insulating part 60, the insulating part 60 will be specifically described below.

Insulating portion 60 includes insulating paper 61 that insulates between U-phase coil 32 and V-phase coil 34, and insulating paper 62 that insulates between V-phase coil 34 and W-phase coil 36. . The insulating paper 61 is an annular insulating member having a relative dielectric constant ε ₁ and is disposed between the U-phase coil 32 and the V-phase coil 34 that are provided in the three-phase rotating electrical machine 11 in a substantially annular shape. The insulating paper 62 is also the same insulating member and is disposed between the V-phase coil 34 and the W-phase coil 36 that are provided in the three-phase rotating electrical machine 11 in a substantially annular shape.

The insulating paper 61 having a relative dielectric constant ε ₁ is disposed between each U-phase coil end portion 322 and each V-phase coil end portion 342 due to the arrangement of the insulating portion 60 described above. Further, after the insulating paper 61 is disposed, a varnish having a relative dielectric constant ε ₁ is impregnated, and then the varnish is heated and cured to form an object 51 that fills the gaps 70 and 80. As a result, a capacitance 46 (relative permittivity ε ₁ ) is formed between each U-phase coil end portion 322 and each V-phase coil end portion 342. Since an object 51 is buried between adjacent U-phase coil end portions 322 of the same phase, an electrostatic capacitance 42 (relative permittivity ε ₁ ) is formed, and a slot inner portion and a tooth of each coil are formed. Since an object 52 is buried between the capacitor 22 and the capacitor 22, a capacitance 44 (relative permittivity ε ₂ ) is formed.

  Next, the operation of the three-phase rotating electrical machine 11 having the above configuration will be described with reference to FIGS. When the three-phase rotating electrical machine 11 is driven by an inverter circuit, a surge voltage with a sharp rise and a high peak voltage is generated between the phases at the moment of switching of the inverter circuit. Applied to the input terminal.

Here, since the relative permittivity ε ₁ > relative permittivity ε ₂ , the values of the capacitance 42 and the capacitance 46 are larger than the value of the capacitance 44. Therefore, as in the case of the three-phase rotating electrical machine 10, even when a surge voltage is applied to the U-phase input terminal 12, the V-phase input terminal 14, or the W-phase input terminal 16, A surge current flows toward the coil on the neutral point 13 side via the capacitors 42 and 46, and the high-frequency current to each coil is dispersed. Thereby, the insulation performance of the U-phase coil 32, the V-phase coil 34, and the W-phase coil 36 can be ensured.

In the above, between each U-phase coil end portion 322 and each V-phase coil end portion 342, there is an insulating paper 61 having a relative dielectric constant ε _{1 and} an object 51 filling the gaps 70 and 80. Although the capacitance 46 (relative permittivity ε ₁ ) is formed, even if only the insulating paper 61 is present and the capacitance 46 is formed, the values of the capacitance 42 and the capacitance 46 are static. As long as the value is larger than the value of the capacitance 44, the same effect can be obtained.

FIG. 6 is a diagram illustrating a result of confirming the effects of the three-phase rotating electrical machines 10 and 11. The vertical axis in FIG. 6 is a diagram showing the maximum potential difference share between coils of the three-phase rotating electrical machine. The graph 101 shows that the relative dielectric constant ε ₁ is 3 in the gaps 70 and 80 between the coil end portions of the coil in the three-phase rotating electric machine, and the relative dielectric constant ε is in the gap 90 between the slot portion of the coil and the teeth 22. The value of ₂ indicates the voltage sharing rate when the varnish of 3 is impregnated. The graph 102 shows the voltage sharing rate when a similar varnish is impregnated with a varnish having a relative dielectric constant ε ₁ of 20 and a relative dielectric constant ε ₂ of 20. A graph 103 shows the voltage sharing ratio when a varnish having a relative dielectric constant ε ₁ of 20 and a relative dielectric constant ε ₂ of 3 is impregnated in the same gap.

In the case of the graph 101, the relative dielectric constant ε ₁ and the relative dielectric constant ε ₂ are both 3 and the same value. In the case of the graph 102, the relative dielectric constant ε ₁ is larger than that in the graph 101. And the relative dielectric constant ε ₂ are both 20 and the same value. Here, in the case of the graph 101, the capacitances 42, 44, and 46 have almost the same value, and a large amount of surge current flows through the other first coil directly connected to the input terminal. As shown in FIG. In the case of the graph 102, the capacitances 42, 44, and 46 are larger than those in the case of the graph 101. However, the relationship remains unchanged, and the capacitance is much higher in the other first coil directly connected to the input terminal. Since the surge current flows, the voltage sharing ratio is the same as that of the graph 101.

On the other hand, in the three-phase rotating electrical machines 10 and 11 according to the embodiment of the present invention, for example, the value of the capacitance 44 is suppressed low by setting the relative dielectric constant ε ₂ to 3, for example, the relative dielectric constant ε _{1 is set} to 20 By increasing the values of the capacitances 42 and 46, the dispersion of the surge current is promoted, and the voltage sharing ratio can be reduced as compared with the graphs 101 and 102 as shown in FIG.

1 is a top view of a three-phase rotating electrical machine that is a first embodiment of the present invention. It is AA sectional drawing in FIG. It is the circuit diagram which showed the three-phase rotary electric machine per element. It is a top view of the three-phase rotating electrical machine that is the second embodiment of the present invention. It is AA sectional drawing in FIG. It is a figure which shows the result of having confirmed the effect of the three-phase rotary electric machine of 1st Embodiment of this invention, and the 3-phase rotary electric machine of 2nd Embodiment of this invention.

Explanation of symbols

  8 Stator, 10, 11 Three-phase rotating electrical machine, 12 U-phase input terminal, 13 Neutral point, 14 V-phase input terminal, 16 W-phase input terminal, 18 Stator yoke, 22 teeth, 24 slots, 32 U-phase coil, 34 V-phase coil, 36 W-phase coil, 42, 44, 46 Capacitance, 51, 52 objects, 60 Insulating part, 61, 62 Insulating paper, 70, 80, 90 Gap, 101, 102, 103 Graph, 221 Side wall , 321 1 U phase coil, 322 U phase coil end part, 323 2 U phase coil, 324 U phase slot part, 325 3 U phase coil, 341 1 V phase coil, 342 V phase coil end part, 343 2 V phase Coil, 345 third V phase coil, 361 first W phase coil, 362 W phase coil end portion, 363 second W phase coil, 36 The 3W-phase coil.

Claims (6)

A plurality of tooth portions, a slot portion formed between adjacent tooth portions, and a three-phase coil wound around the tooth portion, the in-phase coils are provided side by side in the circumferential direction, and the different phase coils are arranged in the radial direction. A three-phase rotating electrical machine including a three-phase coil provided in
In the coil end portion located outside the slot portion of each coil , the relative dielectric constant between the in-phase coils and between the different-phase coils is ε ₁ ,
A three-phase rotating electrical machine characterized in that a relative dielectric constant between an in-slot portion located inside a slot portion of each coil and a tooth portion is ε ₂ , and ε ₁ is larger than ε ₂ . In the three-phase rotating electrical machine according to claim 1,
A three-phase rotating electrical machine, wherein ε ₁ is larger than ₁ . In the three-phase rotating electrical machine according to claim 1 or 2,
In each coil, varnish with a relative dielectric constant of ε ₁ is impregnated between coil end portions,
A three-phase rotating electrical machine, wherein each coil is impregnated with a varnish having a relative dielectric constant of ε ₂ between a slot inner portion and a tooth portion. In the three-phase rotating electrical machine according to any one of claims 1 to 3,
The relative permittivity is ε ₁ only between the coil end portions from the first coil end portion to the third coil end portion on each input terminal side of the three-phase rotating electrical machine. Three-phase rotating electric machine. In the three-phase rotating electrical machine according to any one of claims 1 to 4,
A three-phase rotating electrical machine, wherein ε ₁ is larger than 5 and ε ₂ is smaller than 5. In the three-phase rotating electrical machine according to claim 1 or 2,
A three-phase rotating electrical machine, wherein the coil end portions of each coil are insulated by insulating paper having a relative dielectric constant of ε ₁ .

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